package linkedList;

public class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }

    /**
     * 使用arr为参数，创建一个链表，当前的ListNode为链表头节点
     * @param arr
     */
    public ListNode(int[] arr){
        if(arr == null || arr.length == 0){
            throw new IllegalArgumentException("");
        }

        this.val = arr[0];
        ListNode cur  = this;
        for(int i = 1;i<arr.length;i++){
            cur.next = new ListNode(arr[i]);
            cur = cur.next;
        }
    }

    //以当前节点为头结点的链表信息字符串
    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        ListNode cur = this;
        while (cur != null){
            res.append(cur.val + "->");
            cur = cur.next;
        }
        res.append("NULL");
        return res.toString();
    }
}
